2010 - Accept, Blood of the Nations
2011 - Anthrax, Worship Music
2012 - KISS, Monster / Accept - Stalingrad (tie)
2013 - Stryper, No More Hell to Pay / Newsted, Heavy Metal Music (tie)
2014 - Overkill, White Devil Armory
...of course 2015's not quite over yet but right now Raven's ExtermiNation and Queensryche's Condition Human are neck and neck for the top spot. There are still several new releases (Stryper, Ugly Kid Joe, Motorhead, W.A.S.P.) that I have yet to hear in their entirety.
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"If you're a false, don't entry, because you'll be burned and died!"